S-MTC  (Synonyms: S-Methyl-L-thiocitrulline)

Mixed cortical glial and neuronal cultured cells are prepared from E15 to E18 embryos obtained from Spargue-Dawley rats. On day 7 after plating, the culture medium is removed and replaced with freshly prepared culture medium in the presence of either Aβ_1-42 (1, 5, 10, or 20 μM), Aβ_42-1, or peroxynitrite (100 or 200 μM) with or without either N^G-nitro-L-arginine (L-NOARG,10 or 100 μM), S-MTC (10 or 100 μM), N-iminoethyl-L-lysine (10 or 100 μM), N-(3-(aminomethyl)benzyl)acetamidine (1400W,1 or 5 μM), 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO,10 or 100 μM), or 6-hydorxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (10 or 100 μM) alone or in combination. The cultured cells are then incubated for 20 h. For the time-course studies, the cultured cells are pre-treated with the described culture medium containing Aβ_1-42 (10 μM). Either L-NIL (100 μM), L-NOARG (100 μM), 1400W (5 μM), S-MTC (100 μM), carboxy-PTIO (100 μM) or Trolox (100 μM) are administered at 1, 4, and 8 h later. Assessments are carried out 20 h after Aβ_1-42 administration. The viability of cultured cells is evaluated by using MTT and neutral red colorimetric assays. MTT reduction and NR uptake are quantified at 570 and 540 nm, respectively, by using a micro-plate reader^[1].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

mice^[2]
Male NIH Swiss mice, weighing 18-22 g, are used. S-MTC (1.0 μg/mouse) is administered i.c.v. (15-min pretreatment time). In one set of experiments (#1, #2, and #3), opioid antagonists and NOS-inhibitors are administered 15–30 min prior to the 60-min HBO₂ treatment (180 min prior to antinociceptive testing). In another experiment (#4), opioid antagonist and NOS-inhibitor pretreatment is administered 60 min following cessation of the 60-min HBO₂ treatment (15–30 min prior to antinociceptive testing). For i.p. or s.c. pretreatments, the volume of injection is 0.1 mL/10 g body weight with control animals receiving an i.p. or s.c. injection of vehicle (sterile saline) only. For i.c.v. pretreatments, the volume of microinjection is 5.0 μL per mouse with control animals receiving an i.c.v. microinjection of vehicle (sterile saline) only.
Rats^[3]
Male, Sprague-Dawley rats (350-450 g) are used. On the day after catheterisation (day 1), animals (n=7) receive bolus i.v. injections (0.1 mL) of either saline (vehicle), and 0.3 and 3 mg/kg S-MTC (n=4), or 0.1, 1 and 10 mg/kg S-MTC (n=3). On day 3, the dose regimen is switched to ensure that each animal has received all the doses of S-MTC. On each day, drugs are given in ascending dose-order, and at least 60 min is allowed between doses. The intervening day (day 2) is allowed for wash-out of any drug effects.

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

• [1]. Law A, et al. Neuroprotective and neurorescuing effects of isoform-specific nitric oxide synthase inhibitors, nitric oxide scavenger, and antioxidant against beta-amyloid toxicity. Br J Pharmacol. 2001 Aug;133(7):1114-24.  [Content Brief]

  [2]. Zelinski LM, et al. A prolonged nitric oxide-dependent, opioid-mediated antinociceptive effect of hyperbaric oxygenin mice. J Pain. 2009 Feb;10(2):167-72.  [Content Brief]

  [3]. Wakefield ID, et al. Comparative regional haemodynamic effects of the nitric oxide synthase inhibitors, S-methyl-L-thiocitrulline and L-NAME, in conscious rats. Br J Pharmacol. 2003 Jul;139(6):1235-43.  [Content Brief]